Hello!
Sato's service is excellent, and I can't tell one 
bad thing about him. 
He is charging you for the shipping fees, which 
are pretty exact, and he charges 20% of the end 
price as his commission. Considering that he is 
risking his own money, and is willing to take a 
chance on anyone, I consider this fee very 
agreeable. 
As for how long he is willing to wait for the 
payment, why don't you send him an e-mail and ask 
him personally?